[$] Filesystem test suites

While the 2018 Linux Storage, Filesystem, and Memory-Management Summit(LSFMM) filesystem track session was advertised as being a filesystem test suite "bakeoff", it actually focused on how to make the existing test suites moreaccessible. Kent Overstreet said that he has learned over theyears that various filesystem developers have their own scripts for testingusing QEMU and other tools. He and Ted Ts'o put the session together totry to share some of that information (and code) more widely.